Add IdentityBoth instance for zio.prelude.data.Optional

zio · Nov 13, 2024 · 46f9bf0 · 46f9bf0
1 parent 787c1d6
commit 46f9bf0
Showing 1 changed file with 19 additions and 0 deletions.
diff --git a/core/shared/src/main/scala/zio/prelude/AssociativeBoth.scala b/core/shared/src/main/scala/zio/prelude/AssociativeBoth.scala
@@ -18,6 +18,7 @@ package zio.prelude
 
 import zio._
 import zio.prelude.coherent.CovariantIdentityBoth
+import zio.prelude.data.Optional
 import zio.prelude.newtypes.{AndF, Failure, OrF}
 import zio.stm.ZSTM
 import zio.stream.{ZSink, ZStream}
@@ -1191,6 +1192,24 @@ object AssociativeBoth extends AssociativeBothLowPriority {
         }
     }
 
+  /**
+   * The [[IdentityBoth]] (with [[AssociativeBoth]]) instance for [[Optional]].
+   */
+  implicit val OptionalnIdentityBoth: IdentityBoth[Optional] =
+    new IdentityBoth[Optional] {
+      val any: Optional[Any] = Optional.Present(())
+
+      def both[A, B](fa: => Optional[A], fb: => Optional[B]): Optional[(A, B)] =
+        fa match {
+          case Optional.Present(a) =>
+            fb match {
+              case Optional.Present(b) => Optional.Present((a, b))
+              case Optional.Absent     => Optional.Absent
+            }
+          case Optional.Absent     => Optional.Absent
+        }
+    }
+
   /**
    * The `AssociativeBoth` instance for And `Schedule`.
    */